CN100483731C - Image display system including electroluminescent device and method of manufacturing the same - Google Patents

Abstract

The present invention relates to an image display system including an electroluminescent device and a manufacturing method thereof. The image display system including the electroluminescent device has a plurality of pixel regions, a pair of pixel definition layers separated from each other and surrounding each pixel region, and a reflective layer formed on the surface of the pixel definition layer. The pair of pixel definition layers are separated from each other by a groove, and the reflective layer covers the surface of the groove.

Description

Image display system including electroluminescence device and manufacturing method thereof

technical field

The present invention relates to an image display system including an electroluminescent device and a manufacturing method thereof, in particular to an image display system including an electroluminescent device with high color purity and a manufacturing method thereof.

Background technique

In recent years, with the advancement of electronic product development technology and its increasingly wide application, such as the advent of mobile phones, PDAs and notebook computers, the development of flat-panel displays with smaller volume and power consumption characteristics compared with traditional displays The demand is increasing day by day, and it has become one of the important electronic application products at present. Among flat-panel displays, organic electroluminescent devices will undoubtedly become the best choice for next-generation flat-panel displays due to their characteristics of self-luminescence, high brightness, wide viewing angle, high response speed, and easy process.

An organic electroluminescent device is a light emitting diode using an organic layer as an active layer. In order to be further applied to flat panel displays, it is one of the main trends of current flat panel display technology to develop organic electroluminescent devices with high luminous efficiency and long service life. Therefore, active organic electroluminescent devices with thin film transistors (thin film transistors, thin film transistors) are proposed to avoid the problems caused by passive organic electroluminescent devices. Since the active organic electroluminescent display has the characteristics of surface emission, high luminous efficiency of self-luminescence, and low driving voltage (driving voltage), and has a wide viewing angle, high contrast, high-response speed (high-responsespeed), and Features such as full color. When the size of the display becomes larger, the resolution requirement is higher and higher, and the full-color display is required, the active organic electroluminescent device will undoubtedly become the best choice for the next-generation full-color flat-panel display.

1 is a schematic cross-sectional view of a conventional active organic electroluminescence device 100, including a substrate 10, a thin film transistor array 20, a red LED R, a green LED G, and a blue LED B.

Each LED R, G, and B includes an ITO electrode as an anode 30 , an electroluminescent layer 40 , and a metal electrode as a cathode 50 . Wherein, in order to prevent the light emitted by the red, blue and green light emitting diodes R, G, B from interfering with each other, the pixel definition layer 60 is formed between two adjacent light emitting diodes. However, since in the conventional active organic electroluminescent device 100, a light-transmitting compound is used as the material of the pixel definition layer 60, the side light 42 emitted by the light-emitting diode (such as the red light-emitting diode R) passes through the cathode 50 Reflected into the adjacent light-emitting diodes (such as green and blue light-emitting diodes G, B), this leads to light leakage and luminescent interference, which can easily cause color purity of organic electroluminescent devices and contrast drop.

In order to overcome the aforementioned defects and problems, an opaque compound is used instead of a light-transmitting compound as the pixel definition layer. However, since the opaque compound, such as colorant, is generally a carbon-containing material with a low dielectric constant, the optoelectronic properties of the device will be degraded. In addition, the side light from the light-emitting diode is absorbed by the opaque pixel definition layer, causing the overall luminous efficiency of the organic electroluminescent device to decrease.

Therefore, developing an electroluminescent device structure and process with high color purity without reducing the luminous efficiency of the electroluminescent device is an urgent research focus in the current active organic electroluminescent device technology.

Contents of the invention

In view of this, the purpose of the present invention is to provide an image display system with electroluminescent devices with high color purity, so as to meet the demand of the flat panel display market.

For purposes of the present invention, the image display system includes an electroluminescent device, wherein the electroluminescent device includes a pixel region, a pair of pixel-defining layers, and a reflective layer formed on the pair of pixel-defining layers. Wherein the pair of pixel definition layers surrounds the pixel area, and the pair of pixel definition layers are separated from each other by grooves. In addition, the reflective layer covers the exposed surface of the pair of pixel definition layers, and the reflective layer covers the sidewall and bottom of the trench. Through the configuration of the reflective layer and the pair of pixel definition layers, the side light generated by the electroluminescent device can be sent to the outside, avoiding light leakage and luminescent interference, and greatly Increase the luminous efficiency of the electroluminescent device.

Another object of the present invention is to provide a method for manufacturing an image display system including an electroluminescent device, so as to complete the image display system of the present invention. The method includes the following steps. First, a thin film transistor array substrate is provided, and the thin film transistor array substrate has a plurality of pixel regions. Next, a flat layer is formed on the substrate. Next, a first electrode is formed on the flat layer of each pixel area. Then, a pixel definition layer is formed on the flat layer. Next, the pixel definition layer is patterned to form a pair of pixel definition layers spaced apart from each other, surrounding the pixel area, wherein the pair of pixel definition layers are separated from each other by a groove. Next, an electroluminescent layer is formed on the first electrode. Next, a second electrode is formed on the electroluminescent layer. Finally, a reflective layer is formed on the surface of the pair of pixel definition layers and the trench to cover the exposed surface of the pair of pixel definition layers and completely cover the sidewall and bottom of the trench.

In order to make the above objects and features of the present invention more comprehensible, the present invention will be described in more detail below in conjunction with the accompanying drawings and preferred embodiments.

Description of drawings

FIG. 1 is a schematic diagram showing a cross-sectional structure of a conventional active organic electroluminescent device.

2A to 2G show the manufacturing process of the image display system including the electroluminescent device according to the preferred embodiment of the present invention.

FIG. 3 is a schematic diagram showing the cross-sectional structure of the electroluminescent device according to a preferred embodiment of the present invention.

FIG. 4 is a schematic top view showing an electroluminescent device according to a preferred embodiment of the present invention.

FIG. 5 is a schematic diagram showing the configuration of an image display system including an electroluminescent device according to the present invention.

simple notation

Substrate ~ 10; Thin Film Transistor Array ~ 20; Anode ~ 30; Electroluminescent Layer ~ 40; Cathode ~ 50; Pixel Definition Layer ~ 60; Transistor ~ 107; thin film transistor array substrate ~ 110; gate electrode ~ 121; gate insulating layer ~ 123; semiconductor layer ~ 124; source electrode ~ 125; drain electrode ~ 126; source contact area ~ 125'; drain contact region ~ 126'; planar layer ~ 128; contact window ~ 129; first transparent electrode ~ 130; transparent insulating layer ~ 140; a pair of spaced apart pixel definition layers ~ 142; layer ~ 151; green organic electroluminescent layer ~ 152; blue organic electroluminescent layer ~ 153; second electrode ~ 161; reflective layer ~ 162; metal conductive layer ~ 164; side light ~ 180; electroluminescent device ~200; electroluminescent device ~300; display panel ~400; input unit ~500; image display system including electroluminescent device ~600; red light-emitting diode ~R; green light-emitting diode ~G, and blue light-emitting diode ~ b.

Detailed ways

The present invention solves the problems of light leakage and luminescent interference in existing electroluminescent devices by using a reflective pixel definition structure without increasing the complexity of the process. In addition, the side light generated by the light emitting element can be sent to the outside, so the luminous efficiency of the element can be greatly increased.

Hereinafter, with reference to the figures, a method for manufacturing the image display system 200 including the electroluminescent device according to the present invention will be shown.

2G is a schematic cross-sectional view showing the image display system 200 including the electroluminescent device. Please refer to FIGS. 2A to 2G , which show the manufacturing process of the image display system 200 including the electroluminescent device.

As shown in FIG. 2A , firstly, a thin film transistor array substrate 110 is provided, on which red pixel regions R, green pixel regions G, and blue pixel regions B are defined, wherein each pixel region includes a thin film transistor 107 . The thin film transistor includes a semiconductor layer 124 , a gate electrode 121 , a gate insulating layer 123 , a source electrode 125 , and a drain electrode 126 . The thin film transistor 107 may be an amorphous silicon thin film transistor, a low temperature polysilicon thin film transistor, or an organic thin film transistor. In addition, the TFT 107 may include a source contact region 125' and a drain contact region 126', wherein the source contact region 125' and the drain contact region 126' are electrically connected to the source electrode 125 and the drain electrode 126 respectively. link. However, the structure of the thin film transistor shown in the figure is only an example of the present invention, and the structure of the thin film transistor described in the present invention may also be other structures. In this embodiment, the material of the gate insulating layer 123 may be silicon nitride, and the substrate 110 is an insulating substrate, such as a glass or plastic substrate.

Next, referring to FIG. 2B , a flat layer 128 is formed on the substrate 110 to cover the thin film transistor 107 . The flat layer 128 has a relatively low surface roughness, and its material can be a dielectric or insulating material, such as a low-temperature dielectric layer or spin-on-glass (SOG). The flat layer 128 can be organic or inorganic material. Next, the flat layer 128 is patterned to form a plurality of contact windows 129 exposing the drain contact region 126'.

Next, referring to FIG. 2C , a transparent conductive layer is formed on the planar layer 128 , and then the transparent conductive layer is patterned to form a first transparent electrode 130 in the pixel area. The first transparent electrode 130 is electrically connected to the drain contact region 126' through the contact window 129. The first transparent electrode 130 is formed of light-transmitting metal or metal oxide, such as indium tin oxide (ITO), indium zinc oxide (IZO), zinc aluminum oxide (AZO) or zinc oxide (ZnO). The method can be, for example, sputtering, electron beam evaporation, thermal evaporation, or chemical vapor deposition.

Next, please refer to FIG. 2D , a transparent insulating layer 140 is formed on the substrate 110 . The material of the transparent insulating layer 140 can be, for example, a light-transmitting organic compound or a light-transmitting material suitable for optoelectronic display, such as a photopolymerizable resin or a thermally polymerizable resin. It should be noted that the transparent insulating layer 140 is then subjected to a patterning process to form a pair of pixel definition layers 142 spaced apart from each other surrounding the pixel area, as shown in FIG. 2E . One of the technical features of the present invention is that the pair of pixel definition layers 142 are formed outside the pixel regions R, G, and B (approximately outside the first transparent electrode 130), and the pair of pixel definition layers 142 pass through a trench The grooves 145 are spaced apart from each other, wherein the grooves 145 also surround the pixel area. In this embodiment, the groove 145 exposes the surface of the flat layer 128 . In addition, according to another preferred embodiment of the present invention, the trench 145 can be further formed down into the flat layer 128 by etching, please refer to FIG. 3 . Since forming the trench 145 to separate the pair of pixel definition layers 142 and patterning the transparent insulating layer 140 to form the pair of pixel definition layers 142 is the same photolithography process, so compared with the prior art, the method described in the present invention Its process complexity has not increased.

Next, as shown in FIG. 2F, the red organic electroluminescent layer 151, the green organic electroluminescent layer 152, and the blue organic electroluminescent layer 153 are respectively formed in the red pixel region R, the green pixel region G, and the blue pixel area B. The red organic electroluminescent layer 151, the green organic electroluminescent layer 152, and the blue organic electroluminescent layer 153 can be made of organic semiconductor materials, such as small molecule organic materials, polymer compound materials or organometallic compound materials. It can be vacuum evaporation, spin coating, immersion coating, roll coating, inkjet filling, embossing method, embossing method, physical vapor deposition, or other methods of vapor deposition.

Referring to FIG. 2G , the metal conductive layer 164 is conformally formed on the above structure to cover the organic electroluminescence layer, the pixel definition layer 142 , and all surfaces of the bottom and side surfaces of the trench 145 . Wherein, the metal conduction layer 164 formed on the organic electroluminescent layer serves as the second electrode 161 , and the metal conduction layer 164 formed on the bottom and sides of the groove 145 serves as the reflective layer 162 . Therefore, the second electrode 161 and the reflective layer 162 are made of the same material and formed simultaneously in the same step. The first electrode 130, the organic electroluminescent layers 151, 152, 153, and the second electrode 161 constitute a light emitting diode, wherein the first electrode 130 serves as the anode of the light emitting diode and the second electrode 161 serves as the cathode of the light emitting diode . The metal conduction layer 164 is a material capable of injecting electrons into the organic electroluminescent layer, such as a material with a low work function, such as Ca, Ag, Mg, Al, Li, or any alloy thereof. In addition, in some preferred embodiments of the present invention, the reflective layer 162 and the second electrode 161 may also be made of different materials and formed in different steps.

According to the active organic electroluminescent device 300 described in other preferred embodiments of the present invention, the trench 145 separating the pair of pixel definition layers 142 is further formed down into the planar layer (using etching), please refer to FIG. 3 .

FIG. 4 is a schematic top view of the active organic electroluminescent device 200 . The red, green, and blue pixel regions R, G, and B are respectively defined by the surrounding pixel definition layer 142 , and the groove 145 separates the pair of pixel definition layers 142 . Please refer to FIG. 2G, since the reflective layer 162 is formed on the bottom and sidewall of the groove, the light emitted by the organic light emitting diode can be transmitted to the outside through the reflective layer, so there will be no side light 180 to interfere with adjacent pixels. area of the problem (see Figure 2G). Based on the above, the phenomenon of light leakage and light color interference can be avoided to emit light. In addition, compared with the prior art, the luminous efficiency of the image display system including the electroluminescence device described in the present invention is also greatly increased.

Please refer to FIG. 5 , which shows a schematic configuration diagram of an image display system including an electroluminescent device according to the present invention, wherein the image display system 600 including an electroluminescent device includes a display panel 400, and the display panel has the image display system described in the present invention. Active organic electroluminescent device (such as the active organic electroluminescent device 200 shown in FIG. 2G or the active organic electroluminescent device 300 shown in FIG. 3), and the display panel 400 can be, for example, an organic electroluminescent device LED panel. Still referring to FIG. 5 , the display panel 400 may be a part of an electronic device (such as the image display system 600 shown in the figure). In general, the image display system 600 includes a display panel 400 and an input unit 500 coupled to the display panel, wherein the input unit transmits signals to the display panel to make the display panel display images. The image display system 600 can be, for example, a mobile phone, a digital camera, a PDA (Personal Data Assistant), a notebook computer, a desktop computer, a television, a car monitor, or a portable DVD player.

Although the present invention is disclosed above with preferred embodiments, it is not intended to limit the present invention. Those skilled in the art can make some changes and modifications without departing from the spirit and scope of the present invention, so the protection scope of the present invention What is defined in the claims shall prevail.

Claims (17)

1. An image display system comprising an electroluminescent device, comprising: An electroluminescent device, wherein the electroluminescent device comprises: pixel area; a pair of pixel definition layers separated from each other by a trench, wherein the pair of pixel definition layers surround the pixel area and are formed approximately outside the transparent electrode of the pixel area; and A reflective layer, wherein the reflective layer covers the pair of pixel definition layers and the surface of the groove. 2. The image display system comprising an electroluminescent device as claimed in claim 1, wherein the material of the pixel definition layer comprises a light-transmitting organic compound. 3. The image display system comprising an electroluminescent device as claimed in claim 2, wherein the light-transmitting organic compound comprises a photopolymerizable resin or a thermally polymerizable resin. 4. The image display system comprising an electroluminescent device as claimed in claim 1, wherein a material of the reflective layer comprises metal. 5. The image display system comprising an electroluminescent device as claimed in claim 1, wherein the electroluminescent device comprises an active organic electroluminescent device. 6 . The image display system comprising an electroluminescence device as claimed in claim 5 , wherein the pixel area comprises a thin film transistor, and the thin film transistor is electrically connected to the organic light emitting diode. 7. The image display system comprising an electroluminescent device as claimed in claim 6, wherein the organic light emitting diode comprises a first electrode, an electroluminescent layer, and a second electrode. 8. The image display system comprising an electroluminescence device as claimed in claim 7, wherein the reflective layer is electrically connected to the second electrode of the organic light emitting diode. 9. The image display system comprising an electroluminescent device as claimed in claim 7, wherein the reflective layer and the second electrode are made of the same material. 10. The image display system comprising an electroluminescence device as claimed in claim 6, wherein the thin film transistor comprises an amorphous silicon thin film transistor, a low temperature polysilicon thin film transistor, or an organic thin film transistor. 11. The image display system comprising an electroluminescent device as claimed in claim 1, wherein the trench is formed down into a planarization layer, wherein the planarization layer is formed below the pair of pixel definition layers. . 12. The image display system comprising an electroluminescent device as claimed in claim 1, further comprising a display panel, wherein the electroluminescent device constitutes a part of the display panel. 13. The image display system comprising an electroluminescent device as claimed in claim 12, further comprising an electronic device comprising: the display panel; and The input unit is coupled with the display panel, wherein the input unit transmits signals to the display panel to make the display panel display images. 14. The image display system comprising an electroluminescent device as claimed in claim 13, wherein the electronic device is a mobile phone, a digital camera, a personal data assistant, a notebook computer, a desktop computer, a television, a vehicle display, or Portable DVD player. 15. A method of manufacturing an image display system comprising an electroluminescence device, comprising the following steps: A thin film transistor array substrate is provided, and the thin film transistor array substrate has a plurality of pixel regions; forming a flat layer on the substrate; forming a first electrode on the planar layer of each pixel region, wherein the first electrode is a transparent electrode; forming a pixel definition layer on the planar layer; patterning the pixel definition layer to form a pair of pixel definition layers spaced apart from each other, surrounding the pixel area, wherein the pair of pixel definition layers are separated from each other by a trench and formed substantially outside the first electrode; forming an electroluminescent layer on the first electrode; forming a second electrode over the electroluminescent layer; and A reflection layer is formed on the surface of the pair of pixel definition layers and the groove. 16. The method for manufacturing an image display system comprising an electroluminescence device as claimed in claim 15, wherein the reflective layer and the second electrode are formed of the same material in the same step. 17. The method of manufacturing an image display system comprising an electroluminescence device as claimed in claim 15, wherein the trench is further formed downward into the planar layer.

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